New from Moviestuff

[aj]

Having become recently dubious about almost everything lately (my own assumptions the most) I'm somewhat reluctant to post this - but it reads as quite reasonable:

http://photo.net/learn/orange-negative-mask


Carl

Seems the writer (by Donl Mathis, 1994) in your link didn't know/understand either. I don't understand what the positive-positive Cibachrome has got to do with it and why that comes up.
The one commenter there seems to know better

Early (50-ies) color-negative had no orange bearer and was plain reversed registration. I have several of these really old films in my MINOX kleinstbildkamera collection. Really faint images today.
Apparently handling was difficult and the orange bearer was brought in to raise minimum-levels. The print-paper was tuned to the orange minimum and had then an easier task in rendering the proper colors.
There must some Kodak papers on this invention. If it was Kodak.
It really saved the day for consumer color photography.

The photographic colornegative process is very much Yellow/Magenta/Cyan sensitivity driven. Not RGB. Also it is not lineair. To get the full information form it one needs a 14 bit scan. Especially to read the toe and top of the curves in detail. 8 bit is far too little.

The trick when digital scanning and reverse is to subscract the orange from measured RGB values and then reverse the image. What the photoshop article does explain in my understanding.

[carllooper]

Having become recently dubious about almost everything lately (my own assumptions the most) I'm somewhat reluctant to post this - but it reads as quite reasonable:

http://photo.net/learn/orange-negative-mask


Carl

Seems the writer (by Donl Mathis, 1994) in your link didn't know/understand either. I don't understand what the positive-positive Cibachrome has got to do with it and why that comes up.
The one commenter there seems to know better

Early (50-ies) color-negative had no orange bearer and was plain reversed registration. I have several of these really old films in my MINOX kleinstbildkamera collection. Really faint images today.
Apparently handling was difficult and the orange bearer was brought in to raise minimum-levels. The print-paper was tuned to the orange minimum and had then an easier task in rendering the proper colors.
There must some Kodak papers on this invention. If it was Kodak.
It really saved the day for consumer color photography.

The photographic colornegative process is very much Yellow/Magenta/Cyan sensitivity driven. Not RGB. Also it is not lineair. To get the full information form it one needs a 14 bit scan. Especially to read the toe and top of the curves in detail. 8 bit is far too little.

The trick when digital scanning and reverse is to subscract the orange from measured RGB values and then reverse the image. What the photoshop article does explain in my understanding.

Good point about sensitivity. While the film is sensitive to light it is the density of the dyes that ultimately represent that sensitivity and since one talks about dyes in terms of CMY, then one can describe the sensitivity of the film in terms of CMY, as they do in a film data sheet. For example, for a strong blue light around 450nm, it would be represented in the film by a high amount of yellow dye, but no magenta and cyan.

That said I tend to re-read the CMY dyes in terms of the light that such dyes subsequently blocks/transmit (during datacine, projection, or just eyeballing it). So, for example, for a strong Yellow dye presence, and no Magenta and Cyan in the film, I'd re-read this as the amount of Red and Green light that such a dye transmits, and the Blue that it blocks, my interest (up until recently) being more in the light, than the dyes.

But I'll have to dig a bit deeper into this - it's really quite interesting - chase up some Kodak papers, as you suggest.

Good point about 14 bit encoding. If you get a high enough encoding bandwidth you could forgive 2 bits of lost bandwidth. On the other hand, using a prefilter stage means you could then regain that extra 2 bits, ie. getting 14 bits of yellow instead of 12 bits.

Carl

ps. this one looks like a good start:

http://motion.kodak.com/motion/uploaded ... -image.pdf

pps. on second thoughts it doesn't say much at all

Found this gem though:

http://www.guardian.co.uk/film/2012/sep ... iest-world

[Andreas Wideroe]

pps. the problem with a physical filter (such as a bluish filter) in the optical path of the transfer unit is that it wouldn't work.

I haven't read most of the posts here, but thought I'd just mention that in a professional telecine machine, like the FDL-90 and Quadra that we have here there's a cyan filter that jumps in into the lightpath when the scanner is switched to negative mode.

/Andreas

[carllooper]

pps. the problem with a physical filter (such as a bluish filter) in the optical path of the transfer unit is that it wouldn't work.

I haven't read most of the posts here, but thought I'd just mention that in a professional telecine machine, like the FDL-90 and Quadra that we have here there's a cyan filter that jumps in into the lightpath when the scanner is switched to negative mode.

/Andreas

Yeah - following where I said that, I go on to prove myself wrong, and say:

Or in summary - TScan's idea is just fine - I was in error.

Carl

ps. I need to somehow switch off my stream of consciousness propositional mode and switch on the critical mode, but it's as if my critical mode doesn't want to kick in until I've first proposed something stupid.